Unigas RX1025.1, Manual, Page: 23 / 80

PART III: OPERATION
23
Fig. 6 - Burner control panel
Gas operation

Check that the control box is not in the lockout position; in case unlock it by pressing the relevant key (for further information on the
LMV.., see the related manual).

Check that the pressure switches/thermostats series enables the burner operation.

Check that the gas pressure is sufficient (signalled by an error code on the AZL.. display).

At the beginning of the start-up cycle, the actuator drives the air damper to the maximum opening position, then the fan motor
starts up: the pre-purge phase begins. During the pre-purge phase, the air damper complete opening is signalled by the light
B2 on
(see front panel).

At the end of the pre-purge, the air damper is driven to the ignition position, the ignition transformer is energised (signalled by the
light
B4 on the front panel) then, few seconds later, the EV1 and EV2 gas valves are energised (light G1 and G2 on the front
panel).

Few seconds after the gas valves opening, the ignition transformer is de-energised and light B4 turns to off.

The burner operates in the low flame stage; few seconds later the two-stages operation begins and the burner output increases or
decreases, driven by the external thermostats (progressive burners) or by the modulator (fully-modulating burners).
.
AIR FLOW AND FUEL ADJUSTMENT
WARNING! During commissioning operations, do not let the burner operate with insufficient air flow (danger of
formation of carbon monoxide); if this should happen, make the fuel decrease slowly until the normal combustion
values are achieved.
WARNING! the combustion air excess must be adjusted according to the values in the following chart.
Recommended combustion parameters
Fuel
Recommended (%) CO
2
Recommended (%) O
2
Natural gas 9 ÷ 10 3 ÷ 4.8
Keys
S1 Main switch
S2 Reset pushbutton for control box
S3 CMF switch (0=stop, 1=low flame, 2=high flame,
3=automatic) - fully modulating burners only
B1 Lock-out LED
B2 Hi-flame operation LED
B3 Lo-flame operation LED
B4 “Ignition transformer operation” LED
B5 “Fan motor overload tripped” LED
B6 Stand-by signalling lamp
G1 Gas valves EV2 operation signalling lamp
G2 Gas valves EV1 operation signalling lamp
G3 Gas pressure switch signal lamp
G4 Gas proving system lockout signalling lamp
A2 AZL..
P1 “Gas in the network” signalling LED (pilot)
P2 “Solenoid valve EVP operation” LED
S1 S3
A2
G2
G1
G3
G4
B1
B2 B3 B4
B5
B6
S2
P1
P2